Effects of different adhesion promoters and deproteinizing agents on the shear bond strength of orthodontic brackets: An in vitro study.

OBJECTIVE: To evaluate the effects of different adhesion promoters, namely, Enhance LC, Ortho Solo, Assure Universal Bonding Resin and deproteinizing agents such as 5.25% NaOCl, 10% papain gel on the shear bond strength of orthodontic brackets. MATERIALS AND METHOD: The present study was approved by the Ethics Committee of Teerthanker Mahaveer Dental College and Research Centre, affiliated to Teerthanker Mahaveer University, Moradabad, India. Around 150 extracted sound human upper bicuspids were taken and divided into six groups. Group 1 control (37% H3PO4), Group 2 (37% H3PO4 + Ortho Solo), Group 3 (37% H3PO4 + Assure Universal Bonding Resin), Group 4 (37% H3PO4 + Enhance LC), Group 5 (5.25% NaOCl + 37% H3PO4), and Group 6 (10% papain gel + 37% H3PO4). In all the groups (n = 150) orthodontic metal brackets were bonded with TransbondTM XT and all the samples were subjected for evaluation of shear bond strength using Instron universal testing machine at a cross speed of 0.5 mm/min. The bracket failure mode was examined using Adhesive Remnant Index (ARI). The Kruskal-Wallis test and the Mann-Whitney test were used to compare the shear bond strength. The Chi-square test was used to determine significant differences in the ARI scores among the groups. The significance for all statistical tests was P < 0.05. RESULTS: Mean values of shear bond strength showed statistically significant differences between the evaluated groups (P < 0.005). The lowest and highest shear bond strength was attributed to Group 1 (control) and Group 2 (Ortho Solo), respectively. No statistically significant difference was noted for the mean ARI scores between control, adhesion promoters, and deproteinized group (P < 0.05). CONCLUSION: It was concluded that adhesion promoters and deproteinizing agents can be used to enhance the shear bond strength of orthodontic brackets. Among all the groups Ortho Solo showed the highest bond strength when used with TransbondTM XT.